中文摘要：

以某小型压水堆为研究对象,运用MELCOR程序建立事故分析模型,研究了不可隔离小破口合并全船断电始发严重事故下舱室放射性活度变化规律。结果表明：不可隔离小破口事故下,倘若安全设施失效,将导致堆芯熔化;堆舱放射性活度比其相邻舱室高4个量级。在此基础上,开发了小型堆典型严重事故下辐射场可视化系统,可为舱室剂量评估和核应急决策提供支持。

英文摘要：

The MELCOR program,is used to establish an accident analysis model for a ship′s pressurized water reactor.An investigation is conducted into the changes of cabin radioactivity in the case of a severe accident induced by the small LOCA which cannot be isolated from the power failure in the ship.The results show that if the safety measures are invalid,the core will be melted due to this accident.The radioactivity of the reactor cabin is 4orders of magnitude higher than that of the adjacent cabin.For this reason,the visualization system of the radiation field of small reactor is developed with regard to a typical serious accident.The system can provide support for the assessment of cabin dose and the nuclear emergency decision-making.